The MIG process is a welding mode essentially reserved for the assembly of sheet metals. In addition to its ease of use, it gives excellent results without unduly deforming the metal and without damaging the surrounding elements.
● Attention! The arc is very violent and UV can damage the eyes. The mask, screen or cassette must be approved and adapted.
● To achieve the weld bead, the direction of movement of the torch does not matter. You can work by pulling or pushing.
● When changing the cylinder, never lubricate the regulator connection. Always use a new Teflon gasket.
MIG (Metal Inert Gas) is akin to arc welding. But instead of changing the worn electrode, a coil of wire continuously supplies the filler metal needed for welding. The diffusion of a neutral gas, often based on argon and carbon dioxide, protects the weld pool by avoiding oxidation and facilitating its cooling.
The energy generator is a transformer associated with a rectifier. It converts the AC 230 V sector into a DC voltage, capable of providing an adjustable high current. The terminals of the generator are joined internally: + the mechanism of advance of the wire; the - to the mass gain.
● The filler wire unwinds regularly, driven by motorized rollers, through a sheath to the torch. This includes a handle, a trigger and a terminal nozzle. The welding wire passes through the duct of the handle and then passes through a calibrated guide tube. Itself is surrounded by the casing tube intended to channel the protective gas at the point of welding. Thus the guide tube assembly and tube-envelope constitute the nozzle. The trigger manages the advance of the wire and the arrival of the gas.
● On the control panel, two graduated buttons are used for settings. One controls the speed of advance of the wire, the other acts on the welding intensity. The gas cylinder, here Atal for welding of ferrous metals, is marketed in 0.5 1 and 4 m3. The head has two manometers: one to indicate the amount of gas remaining in the bottle, the other to display the gas flow to the nozzle. Initially, the pressure is 200 bar.
First you have to protect your eyesight.
The most practical mask is the cassette hood. Powered by a battery, it has a screen that illuminates to view the work at startup. It darkens automatically as soon as the arc is primed.
● Connect the machine to the power supply and set the wire feed speed (V) and the welding current (I) to the front depending on the thickness of the sheets to be bonded and the diameter of the welding wire. Here 0.6 mm, but it also exists in 0.8 mm. A table provided by the manufacturer gives the values to display. Example: assembly in overlap of two sheets of thickness 1 mm: V = 6.5; I = 5.
● Position the two plates to be assembled and flange them with the earth clamp or a vice clamp. Open the tap on the Atal bottle and adjust the flow with the button
operating the regulator. Display 10 l / min on the gauge.
● Point the weld seam with the nozzle and squeeze the trigger: the wire advances, touches the metal and the arc starts. By uniformly moving the slightly inclined nozzle, the weld bead is formed. It is cooled immediately by the gas. To avoid deformations, and if the part is a bit wide, it is recommended to perform the welding in two times starting from the ends towards the center. There is no slag to stitch, unlike the arc welding.
Open the faucet on the bottle. The left pressure gauge shows the amount of gas remaining. Turn the regulator knob until the right pressure gauge is at 10 l / min.
The table inside a panel of the device gives the graduations to display. I = intensity and V = wire running speed, depending on the diameter of the wire and the thickness (T) of the sheets to be welded.
To weld a 1 mm T-iron sheet with Atal gas (Ar + CO2) and a Ø 0.6 mm welding wire, the table shows the graduations V = 6.5 and I = 5. Display these values on the corresponding buttons.
The disassembled side panel unveils the spool of thread and its roller drive. If necessary, adjust the roller pressure on the wire for proper scrolling without skidding.
The torch equipped with a trigger ends with a diffuser nozzle where the 0.6 mm thread guide is screwed. The casing pipe caps everything and channels the gas on the weld. Clean this set often.
To assemble two sheets, place the clamp and adjust your mask. By simply pressing the trigger of the torch, the wire advances and the arc begins in contact with the weld with the metal.
The bow springs and it remains only to guide the slightly inclined torch. To avoid distortion, it is best to make the cord twice from each end to the center.
Another application: the square assembly of two pieces of sheet metal. Place the two pieces edge to edge to form an L. Point in three places then pull a continuous cord, the torch at 45°.